Separation and quantification of the major daucane esters of Ferula hermonis by HPLC.

A simple HPLC method was developed to quantify the major daucane sesquiterpene esters present in herb and roots of Ferula hermonis Boiss. The method utilized a C(18) reversed phase analytical column with isocratic elution for 30 minutes and UV detection at 240 nm. Extracts from two crude plant samples and two commercial products were fingerprinted and quantitatively analyzed.

Inhibitory effects of maesanin and analogs on arachidonic acid metabolizing enzymes.

The substituted 1,4-benzoquinone, maesanin (1), is a potent 5-lipoxygenase (5-LO) inhibitor present in the fruit of Maesa lanceolata Forssk. Thirteen natural, synthetic, semisynthetic, and microbially transformed analogs of 1 were tested for their in vitro inhibition of 5-lipoxygenase (5-LO) and cyclooxygenase-1 (COX-1). Maesanin was the most active 5-LO inhibitor. All other analogs were inactive or less active than the natural products as 5-LO inhibitors. None of the tested compounds was strongly active in the COX-1 inhibition assay.

Alkaloids from Haplophyllum tuberculatum.

Two new alkaloids, haplotubinone (3) and haplotubine (4), were isolated from the aerial parts of Haplophyllum tuberculatum together with the known lignan diphyllin. The structures of the new alkaloids were established by spectroscopic methods in conjunction with X-ray crystallographic analysis of 3. In addition, the amide N-(2-phenylethyl)-benzamide has been identified in this source for the first time.

Daucane sesquiterpenes from Ferula hermonis.

The roots of Ferula hermonis Boiss yielded two new daucane esters, 14-(4'-hydroxybenzoyloxy)dauc-4,8-diene (1) and 14-(4'-hydroxy-3'-methoxybenzoyloxy)dauc-4,8-diene (2), together with the four known sesquiterpenes jaeschkeanadiol p-hydroxybenzoate (3), jaeschkeanadiol benzoate (4), jaeschkeanadiol (5), and epoxyjaeschkeanadiol (6). The identities of the isolated compounds were ascertained primarily using NMR and MS data. Compounds 1 and 3 exhibited antimicrobial activity against Staphylococcus aureus with IC(50) 1.5 and 3.5 microg/mL, respectively, and against Methicillin-resistant S. aureus with IC(50) 2.0 and 4.0 microg/mL, respectively.

Bioactive 12-oleanene triterpene and secotriterpene acids from Maytenus undata.

The aerial parts of Maytenus undata yielded four new 12-oleanene and 3,4-seco-12-oleanene triterpene acids, namely, 3-oxo-11alpha-methoxyolean-12-ene-30-oic acid (1), 3-oxo-11alpha-hydroxyolean-12-ene-30-oic acid (2), 3-oxo-olean-9(11), 12-diene-30-oic acid (3), and 3,4-seco-olean-4(23),12-diene-3, 29-dioic acid (20-epi-koetjapic acid) (5), together with the known 3, 11-dioxoolean-12-ene-30-oic acid (3-oxo-18beta-glycyrrhetinic acid) (4), koetjapic acid (6), and the 12-oleanene artifact 3-oxo-11alpha-ethoxyolean-12-ene-30-oic acid (7). Koetjapic acid (6) inhibited the growth of Staphylococcus aureus, methicillin-resistant S. aureus, and Pseudomonas aeruginosa, with an MIC range of 3.125-6.25 microg/mL. The new 3,4-secotriterpene acid 20-epi-koetjapic acid (5) potently inhibited rat neonatal brain microglia phorbol ester-stimulated thromboxane B(2) (IC(50) = 0.5 microM) and superoxide anion (IC(50) = 1.9 microM) generation.

2-Hydroxy-5-(ethanolamino)-3-(10'-Z-pentadecenyl)-1,4-benzoquinone, new microbial phase II metabolite of maesanin.

The use of microbial models for biotransformation of the natural benzoquinone, maesanin (1), resulted in the isolation of an ethanolamine conjugate (5) from the culture broth of Debaryomyces polymorphus ATCC 20280. Metabolite 5 was characterized as 2-hydroxy-5-(ethanolamino)-3-(10'-Z-pentadecenyl)-1,4-benzoq uinone. The production of 5 represents a new type of phase II conjugation reaction in microbial systems. The results of preliminary mammalian metabolism of 1 in rats were inconclusive.

Artemisinin-derived sesquiterpene lactones as potential antitumour compounds: cytotoxic action against bone marrow and tumour cells.

We determined the in vitro cytotoxic activity of the sesquiterpene lactone endoperoxide artemisinin (1) and some chemically prepared derivatives, which have been found to display cytotoxicity to cloned murine Ehrlich ascites tumour (EAT) cells and human HeLa cells and against murine bone marrow using a clonogenic assay for committed progenitor cells of the granulocyte-monocyte lineage (CFU-GM assay). Comparing artemisinin (1) to deoxyartemisinin (2), the endoperoxide group appeared to play a role in cytotoxicity to CFU-GM cells. Dimers of dihydroartemisinin and dihydrodeoxyartemisinin revealed that the stereochemistry of the ether linkage of the dimers was a more important determinant for this cytotoxic activity. The nonsymmetrical dimer of dihydroartemisinin (3) and the corresponding endoperoxide-lacking dimer of dihydrodeoxyartemisinin (5) were equally cytotoxic to CFU-GM cells. Despite the differences between both systems, it may be stated that most compounds displayed higher cytotoxicity to CFU-GM cells than to EAT cells. Dimers of dihydroartemisinin (3, 4) were selected as potential antitumour compounds and subjected to the National Cancer Institute drug-screening programme consisting of about sixty human cancer cell lines derived from nine different tissues. Both compounds displayed the same specific cytotoxicity pattern. Throughout the screen dimer 3 was more active than 4.

Cell culture assay system for the evaluation of natural product-mediated anti-Hepatitis B virus activity.

Utilizing the hepatitis B virus (HBV)-producing hepatoblastoma cell line, HepG2.2.15, which is stably transfected with the cloned HBV genome, methods were devised to examine the effects of test substances on intracellular extrachromosomal HBV DNA levels and secretion of hepatitis B surface antigen (HBsAg). The known inhibitor of HBV replication, dideoxycytosine (ddC), had a minor effect on the secretion of HBsAg, but >90% of intracellular extrachromosomal HBV DNA expression was lost at a non-cytotoxic drug concentration (25µM). This inhibitory effect was reversed when ddC was removed from the medium. Of 19 plant materials tested, extracts from the aerial parts of Clematis sinensis Lour, and Clerodendron inerme R. Br. significantly inhibited the secretion of HBsAg into the culture medium at non-cytotoxic concentrations, but had no effect on intracellular extrachromosomal HBV DNA levels. This system is useful for the evaluation of test materials, or combinations of test materials, for their potential to inhibit HBV markers.

Isolation and characterization of two antimicrobial agents from mace (Myristica fragrans).

The two antimicrobial resorcinols malabaricone B [1] and malabaricone C [2] were isolated from mace, the dried seed covers of Myristica fragrans. Both compounds exhibited strong antifungal and antibacterial activities. Structure modifications by methylation or reduction resulted in diminished activity.

Effect of khatamines and their enantiomers on plasma triiodothyronine and thyroxine levels in normal Wistar rats.

The effect of cathinone and N-formylnorephedrine, two psychoactive amines of khat (Catha edulis Forsk.) and their enantiomers have been studied on plasma levels of triiodothyronine (T3) and thyroxine (T4) in male Wistar rats. The rats were injected with 5, 10 and 30 mg/kg, body weight of four khatamines and the blood samples were collected 2 h after their administration. In the separate set of experiments the effect of these khatamines at 1, 2 and 4 h after their administration was also examined. All the khatamines failed to produce a significant dose dependent increase in T3 and T4 levels in the dose of 5 mg/kg. However, all of these compounds produced a significant dose dependent increase in T3 and T4 levels at higher doses but only T4 levels were increased following the dose of 10 mg/kg. Our studies on the effect of khatamines in T3 and T4 levels at various times showed a significant increase in T4 levels in all the four groups treated with various khatamines and the peak effect was observed at 2 h in case of (-)- and (+)-cathinone and 4 h in case of (-) and (+)N-formylnorephedrine. This study suggests that the symptoms observed in khat chewers including hyperthermia, anorexia, and metabolic changes may to some extent be attributed to the thyroid stimulating effect of khatamines. However, further studies are needed to establish the mechanism of release of thyroid hormones by these compounds and their involvement in the pharmacological effects.

Isolation and identification of an anti-inflammatory principle from Capparis spinosa.

The homologous polyprenols cappaprenol-12 (1), cappaprenol-13 (2) and cappaprenol-14 (3) with 12, 13 and 14 isoprene units, respectively, could be isolated by preparative HPLC from alcoholic extracts of Capparis spinosa. Testing 2 for its anti-inflammatory activity an inhibition of the carrageenan-induced paw edema in rats of 44 vs. 67% for the standard oxyphenbutazone was found.

Antimicrobial activity of phenolic constituents of Magnolia grandiflora L.

Three phenolic constituents of Magnolia grandiflora L. were shown to possess significant antimicrobial activity using an agar well diffusion assay. Magnolol, honokiol, and 3.5'-diallyl-2'-hydroxy-4-methoxybiphenyl exhibited significant activity against Gram-positive and acid-fast bacteria and fungi. The minimum inhibitory concentrations were determined for each compound using a twofold serial dilution assay.

Isolation and characterization of the sesquiterpene lactones costunolide, parthenolide, costunolide diepoxide, santamarine, and reynosin from Magnolia grandiflora L.

The germacranolide sesquiterpene lactones costunolide, parthenolide, and costunolide diepoxide were isolated from the leaves of Magnolia grandiflora L. Costunolide diepoxide might be, at least in part, an artifact derived from air oxidation of parthenolide. The root bark yielded only costunolide together with the two eudesmanolides, santamarine and reynosin. In an attempt to synthesize costunolide diepoxide, the action of m-chloroperbenzoic acid on parthenolide and on costunolide was studied. The products were costunolide diepoxide from parthenolide and the two cyclized derivatives, santamarine and reynosin, from costunolide. The elusive 1,10-epoxide was obtained by epoxidizing costunolide using a biphasic system containing sodium bicarbonate. Under these conditions, epoxidation of costunolide took place without cyclization.